@user67760, for future reference. please create a new topic in it's own thread when requesting new off topic subject matter, and especially when the thread has matured. This will also assist others, should they have the exact question, as your post title will contain the exact issue they are seeking the answer to.
re: 'Where is the button on the puk.js PCB?' (sic puk.js -> Puck.js)
Ref image half-way down page:
The button is activated as the case is compressed. Although not shown in the that image, the button is on the opposite side between D1 and D31, adjacent to the battery holder, opposite where the battery is inserted.
Where is the button on the puk.js PCB? I cannot see a button anywhere.